As materials having bioactive functions, a variety of materials have been proposed including polyphenols as those having bioactive functions such as antioxidative effect, antihypertensive effect and hepatic function-improving effect (Patent Document 1)
Chlorogenic acids, which are one class of polyphenols, have been reported to be high in antihypertensive effect (Patent Document 2), and are expected to find a wide range of utility in supplements and diet.
Developments have hence been carried out to provide the chlorogenic acids with a higher purity and a stability. As a process for the production of a stable purified chlorogenic acid extract, for example, there has been proposed a process that adjusts a coffee extract to a specific solids concentration and then brings it into contact with acid clay and/or activated clay (Patent Document 3).